package Text;

import Text1.Solution1;

public class Solution {
    class ListNode{
        int val;
        ListNode next;
        ListNode() {}
        ListNode(int val) {
            this.val = val;
        }
        ListNode(int val, ListNode next) { this.val = val; this.next = next; }
    }

    public ListNode reverseList1(ListNode head) {
      ListNode pre=null;
      ListNode cur=head;
      while(cur!=null){
          ListNode tmp=cur.next;
          cur.next=pre;
          pre=cur;
          cur=tmp;
      }
      return pre;
    }

    public ListNode reverseList(ListNode head) {
        if(head==null || head.next==null) {
            return head;
        }
        ListNode cur = reverseList(head.next);
        head.next.next = head;
        head.next = null;
        return cur;
    }

}
